1. Field of the Invention
This invention relates generally to a method and apparatus for a specially processed fiber to distribute energy to a medium in which the fiber is embedded. More particularly, this invention relates to a processed fiber embedded in a sealant material that is capable of propagating excess energy through the sealant material without substantial absorption.
2. Description of the Art
Sealant materials are used to repair structure parts of aircraft such as helicopters, by adhering parts that require repair. The sealant material interacts with the structure and can adhere broken portions or seal cracks. Unfortunately, conventional sealant materials used to repair aircraft parts require extended periods of time to adequately cure. This removes the aircraft from active flight status for several hours. Curing the sealant material can be enhanced by using an external source of thermal energy, such as a heating blanket. However, since the sealant material may have poor thermal conductivity, there may be unbalanced curing of the material. For example, a portion of the sealant material in close proximity to the heat source may be over-cured, while a portion of the sealant more remote from the heat source may remain essentially uncured. Thus, the physical properties of the sealant materials necessitate extended cure times causing an aircraft to be removed from active status while the sealant cures.
A second drawback to curing processes that utilize conventional external heat sources is that these heat sources are typically bulky and cumbersome. Application of an external heat source may require removal of components and/or cargo from the aircraft to enable access for the repair operation. Furthermore, the use of a bulky heat source makes access to small areas difficult. Additionally, thermal blankets and electric heat sources may spark and are therefore a fire hazard.
For thick repair regions, the poor thermal conductivity of the sealant material could preclude proper heating of the repair sealant. In order to adequately cure the entire sealant volume, the additional heat often results in over heating, and weakening, of the surrounding regions.
Separately, U.S. Pat. No. 5,770,296 discloses an adhesive device that absorbs electromagnetic waves contiguous with a heat-activatable adhesive material. This reference does not solve the problem of efficient curing because a portion of the adhesive material closest to the heat energy will cure before a portion of adhesive material further from the heat source. This reference is hereby incorporated by reference. Furthermore, this reference does not relate to aircraft or repairing parts on aircraft. Therefore, what is needed to streamline aircraft and other structure repair is a process for repairing damage that is time efficient and does not introduce the unnecessary risk of spark that is present with electric heating blankets. Fibers, such as optical fibers, typically provide a conduit for signals or energy to be transmitted to a destination location, which is usually at a terminal end of the fiber. However, it has been discovered that processing a fiber and embedding the processed fiber in a medium permits energy to be distributed along the length of the fiber and absorbed by the medium generally uniformly. Specifically, embedding processed fibers in a curable sealant material facilitates rapid uniform cure of the sealant.
One embodiment of the instant invention is drawn to a system for adhering a sealant material to a structure. This system comprises an electromagnetic energy source for supplying electromagnetic (EM) energy. The sealant material is mounted on the structure for interfacing with the structure. One or more fibers are embedded in the sealant material for receiving electromagnetic energy from the electromagnetic energy source and transmitting the electromagnetic energy within the sealant material. The sealant material absorbs a quantity of the electromagnetic energy sufficient to cure the sealant material and propagates excess electromagnetic energy through the sealant material without significant additional absorption. The embedded fibers facilitate uniform cure of the sealant material.
A second embodiment of the instant invention is drawn to a method for adhering a sealant to a structure. This method comprises:
disposing the sealant material on at least a portion of the structure;
providing electromagnetic energy to the sealant material;
transmitting electromagnetic energy through the sealant material via fibers embedded in the sealant material thereby curing the sealant material such that the sealant material fixedly adheres to the structure; and
propagating excess electromagnetic energy through the sealant material without substantial absorption of the excess electromagnetic energy by the sealant material.
A third embodiment of the instant invention is drawn to a method for delivering energy to a material using embedded fibers. This method comprises:
providing an energy source for supply electromagnetic energy to a fiber;
processing the fiber such that the fiber emits a portion of the electromagnetic energy from one or more intermediate sections of the fiber; and
embedding the fiber in a material;
wherein the processing is selected from the group consisting of bending, doping, crimping, scratching, coating and etching and combinations thereof.
A fourth embodiment of the instant invention is drawn to an apparatus for delivering energy to a material. This apparatus comprises an electromagnetic energy source for providing electromagnetic energy. One or more processed fibers are embedded in the material. The fibers receive electromagnetic energy from the electromagnetic energy source and disburse at least a portion of the electromagnetic energy from one or more intermediate sections of the fiber to the material.
The fibers are processed using a technique selected from the group consisting of scratching, etching, coating doping, crimping, and bending and combinations thereof.
A fifth embodiment of the instant invention is forming a heating mat with fibers embedded in the mat. The mat can be a heat blanket to provide thermal energy to a structure.
Each of these embodiments is particularly useful in the repairing and reconstruction of aircraft, such as helicopters.